Process of removing pectic matter from vegetable fibers.



ear hen mummy LEEUH, UT MACCLESIIFMW, ENGLAND.

-. but! on MEMUVWG IIPECTIC MATTER lE'MOllll VEGETABLE FIBERS.

To all whom it may concern Be it known that l, BENJAMIN Lenora, sub'ect of the King of Great Britainland he and, residing at 77 Pownall street, Macclesfield, in the county of Chester, England, have invented a new and Tm roved Process of Removing Pectic Matter rom Vegetable Fibers, of which the following is a specification.

This invention relates to the removal of fabric.

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The known methods hitherto in use to carry out this process essentially consist in treating the fibers with an alkali such as caustic soda or sodium carbonate in a solution at a high'temperature. l have discovered that the action of these alkalis consists in the gradual decomposition of the insoluble compounds of pectic acid and the formation of soluble compounds of the alkali with the pectic acid, such for example, as sodium pectate. The chemical action is very slow and in the case of most fibers can only be thoroughly performed within a reasonable time by carrying on the treatment in closed vessels un er a pressure higher than that of the atmosphere.

The treatment of cotton fibers with alkalis under the high temperature involved in this method of treatment is accompanied by a known risk of producing a diminution in their textile strength due to the formation of oxy-cellulose.

My method consists in the treatment of the fibers with an aqueous solution of hydrochloric acid at or near the boilin point containing such an amount of acid that the hydrochloric acid solution while acting on all the pectic matter in the fibers to form free pectic acid and soluble chloride of the bases with which the pectic acid formed an insoluble compound before treatment, will not be suficient in amount to cause. tenderapecification of matters Patent.

Patented ihpr. 2%, ffiffi.

Application filed hugust all, 1917. serial No. name.

ing of the fiber. The chemical action of my improved method takes places with great ease and rapidity and the pectic acid set free thereby is readily removed in part by washing wlth water and in part by treatment with alkaline solutions, such as solutions of ammonia or carbonate of soda.

would have it clearly understood that I am aware that boiling dilute hydrochloric acid has been used in the past for the treatment of vegetable fibers for the removal of pectic matter and I do not claim any novelty with regard to such treatment per so.

In my invention the proportionate amount of hydrochloric acid to the material is of the first degree of importance for the reason that if less than enough acid is present to convert the insoluble ectates' into pectic acid then a residue of insoluble pectate will remain on the fiber. Or, if on the contrary too great an amount of acid is present the physical structure of the fiber is readily attacked and a loss of its tensile strength is brought about.

In order to deal with the proper strength of acid solution I therefore ascertain the amount of acid it is necessary to employ to produce the required change in all the peetic matter of a particular fiber. I may make this estimate either by suitable chemical means or by direct tests of the tensile strength after treatment with solutions of hydrochloric acid of difierent concentrations and thus arriveat the greatest amount of acid which may be used without reducing a practically detrimental loss 0 tensile strength.

As a result of numerous experiments conducted on a big scale I find that the method of arriving by chemical analysis at the quantity of acid required will depend upon the actual condition of manufacture of the fibers it is required to treat. Supposing the fibers to be free from alkaline substances or carbonates added during the process of manufacture, and supposing the material to be treated is in a form in which it is possible to get ready access of the treating liquor by circulating the latter by any usual means to all portions of the material, I find that complete treatment of many ades of American cotton is efiected in hal an hour at the boiling temperature with a solution of 3 grams per liter of hydrochloric acid of "fill stance which has a neutralizing a specific gravity of 1.150 when the proporacid the strength of the solutlon usedmust be increased by an amount chemically equivalent to the quantity of neutralizing substance present in the material treated. If the material is in a form diflicult to penetrate, it is necessary to use an acid of weaker strength at first and to prolong the time of treatment, ultimately however increasing the strength of the acid until the total amount of acid used is suflicient to cause the conversion of all the pectic matter to a soluble form. In general the method I recommend to be followed is first to test small samples of the material to be treated in the following manner. First ascertain the amount of the neutralizing efiect on hydrochloric acid of a known weight of the material. This is done by thoroughly soaking a known Weight of the material in a known volume of cold decinormal hydrochloric acid and then titrating to the point of neutralization with a standard alkali, from which the acid equivalent of alkaline substances in the material is calculated. Next treat, say, six samples of the neutralized material with acid of strengths, 0. g., 2.0, 2.5, 3.0, 4.0, 4.5,

grams per liter respe'cti-vely,fat the boil for one hour. Theproportion mass of liquorv mass of material must be the same as that which will obtain when the bulk is treated. Each sample is then washed thoroughly, treated with hot ammonium hydrate solution of a strength sufiicient to more than neutralize the acid remaining in the samples and dried, after a detrimental tendering may be used for the bulk plus the amount necessary for neutralization, the solution being used at or near the boil for half an hour. If the material is of a form diflicult to penetrate, the strength of the acid used must be low at first and gradually brought up to the limiting strength found by experiment,'the time of treatment'being correspondingly prolonged; this is done to prevent local concentration above the maximum permissible.

It is quite obvious the process may be used in conjunction with other means of removing other impurities, for example, to remove dirt, soap, as a detergent, may be used with the alkali subsequent to the treatment with the acid, or starch may be removed by diastatic fermentation before the treatment with the'aoid solution above. As a result of careful experiment I find that by treating the fibers in accordance with this invention it is possible to effect a saving in time, material, and steam consumption as compared with known methods for preparing the cotton for bleaching or dyeing.

Also I find that the final appearance of the cotton after bleaching is in some cases improved and the risk of damage to the fiber is less than when some of the known methods of preparing the cotton for bleaching are used.

I claim A process for removing pectic matter from vegetable fibers, which consists in thoroughly soaking a known weight of the fibers in a known volume of hot decinormal hydrochloric acid, titrating the fibers to the point of neutralization with a standard alkali, treating the-fibers with hydrochloric acidof a predetermined strength at the boiling point, washing the fibers thoroughly and then treating the fibers with a hot alkaline solution, substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

BENJAMIN LEECH.

Witnesses:

ERNALD S. MOSELEY, J. MANSUR CLOUD. 

